Dendritic mesoporous silica confined nanozyme reactor for one-step and recyclable detection of glucose via biomimetic cascade catalysis

A multifunctional nanozyme-based reactor (FDIG) was rationally constructed by integrating Fe 3 O 4 nanoparticles, Ir nanoparticles, and glucose oxidase (GOx) within the spatially confined framework of dendritic mesoporous silica nanoparticles (DMSN). The DMSN scaffold provides abundant mesochannels and silanol groups for the uniform co-immobilization of catalytic components, enabling efficient oxidase–peroxidase cascade catalysis through a proximity-driven mechanism. In this confined architecture, GOx catalyzes glucose oxidation to produce H 2 O 2 , which is subsequently decomposed by Fe 3 O 4 /Ir nanozymes to generate hydroxyl radicals ( OH) for TMB oxidation, leading to a strong blue colorimetric response. Benefiting from the synergistic interaction between Fe 3 O 4 and Ir and the spatial confinement effect of DMSN, the FDIG nanoreactor exhibits remarkably enhanced peroxidase-like activity, high substrate affinity, and excellent structural robustness. Through a simple one-step detection, the optimized FDIG system demonstrated outstanding glucose-sensing performance with a wide linear range (50–1000 μM), a low detection limit (0.34 μM), and excellent selectivity. Besides, FDIG can be easily separated and reused due to the magnetic Fe 3 O 4 nanoparticles, maintaining over 80% activity after five cycles. The sensor also showed reliable analytical performance in artificial saliva, achieving recovery rates of 95–96% with RSDs below 3.2%, confirming its applicability in complex biological environments. Moreover, the colorimetric response could be quantitatively analyzed via an RGB-based smartphone platform, allowing rapid and instrument-free glucose monitoring, thus demonstrating the potential of FDIG for noninvasive point-of-care testing.